1. Field of the Invention
This invention relates to multifunctional polymers containing polymerized units of    (a) α-acyloxyacrylonitrile, α-haloacrylic acid, α-acyloxyacrylic ester and/or α-hydroxyacrylic acid,    (b) monoethylenically unsaturated carboxylic acids,    (c) vinyl esters of saturated aliphatic monocarboxylic acids and/or vinyl alcohol and optionally    (d) other monoethylenically unsaturated monomers copolymerizable with said monomers (a) to (c) and optionally    (e) crosslinkers containing at least two ethylenically unsaturated double bonds.
2. Description of the Background
U.S. Pat. No. 2,728,746 discloses polymers of α-hydroxyacrylic acid which are prepared by polymerizing α-acyloxyacrylates optionally together with other monomers such as ethylene, styrene, acrylic acid or methacrylic acid and subsequent hydrolysis of the polymerized α-acyloxyacrylate units with bases. DE-A-24 31 823 discloses a process for preparing water-soluble salts of poly-α-hydroxyacrylic acid by converting α,β-dichloropropionic acid by thermal hydrogen chloride elimination into α-chloroacrylic acid, then polymerizing the α-chloroacrylic acid in aqueous solution and treating the polymer with an aqueous solution of an alkali metal hydroxide or ammonia. The water-soluble salts of the thus obtainable poly-α-hydroxyacrylic acid are used for example as sequestrants for metal ions and as builders in detergents and cleaners.
EP-A-381 261 discloses nonaqueous liquid detergents which include a nonionic surfactant and a dispersed particulate phase which includes a carbonate, a mixture of carbonate and bicarbonate builder and a carboxyl-containing polymer, for example a copolymer of maleic acid and acrylic acid. According to the description part, useful carboxyl-containing polymers include poly-α-hydroxyacrylic acid. The liquid laundry detergent may also include bleach.
DE-A-31 39 091 discloses phosphate-free or low-phosphate laundry detergents and cleaners which include a polycarboxylic acid in salt form, an alkali metal heptoate or alkali metal gluconate, an alkali metal silicate and an alkali metal hydroxide. Polycarboxylic acids contemplated are in particular the polymers of acrylic acid, α-hydroxyacrylic acid, maleic acid, itaconic acid, mesaconic acid, arconitic acid, methylenemalonic acid and citraconic acid. Similarly the copolymers of the carboxylic acids mentioned with each other or with ethylenically unsaturated compounds such as ethylene, propylene, vinyl ether, vinyl acetate, furan, acrolein, acrylamide, acrylonitrile, methacrylic acid or crotonic acid are suitable polycarboxylic acids. EP-A-508 934 likewise discloses laundry detergent mixtures which include polymers of hydroxyacrylic acid as builders.
EP-A-814 193 discloses a bleach stabilizer for peroxides which includes homo- or copolymers of α-hydroxyacrylic acid or water-soluble salts thereof, homo- or copolymers of acrylic acid, methacrylic acid and maleic acid and, as a further component, diethylenetriaminepentaacetic acid, diethylenetetraminehexaacetic acid or water-soluble salts thereof. The three components have a synergistic effect when used as a bleach stabilizer for peroxides.